Electric motor



June 8 1926.

H. A. WHITESDE ELECTRIC MOTOR Original Filed Feb.

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\ spring is increased or relaxed by means off Patented J une 8,

i UNITED STATES PATENTOFFICE.

HOWARD A. WHITESIDE, OF NEW YORK, N. Y.

Application filed February 11, 1919, Serial No. 276,449.

ELECTRIC MOTOR.

insulating material.

fully described in tion, set forth in th illustrated in the accompanying in which The invention is more the following specificae appended claims and drawings,

Fig. 1 is a side view of the device, Fig. 2 is a longitudinal sectional View of the same,

Fig. 3 is a inodiied sectional view of one of the bearings,

Fig. fl is a section bearing,

Fig. 5

ing.

al View of the opposite is another modified form of bear- Tlie construction of motors ot small size oiers great difficulties.

In assembling the minute parts the greatest care must be taken that there be no crossing of parts', and when these' motors circuits by these are inclosed inl a hollow handle, means must be provided to prevent short circuiting by the operator.

The device shown the hand of in the drawings is provided with a handle comprising a shellY 10 of non-conductive or insulating material,

such as balcelite, or

11 with threads on its inner edge,

the like, havinga cap lbe screwed on the shell 10. Vithin the latter is an electric. motor with ield coils 12 and laminated magnet 13 around its interior and centrally located is motor is, as shown, any agency the armature 14. The entirely insulated from which might cross-circuit the electric current which is introduced by means of a cord 15 carrying the wire 16 terminating at one brush 18 brush 18, wire 16a and terminating at one iield wire 17 at the other coil terminal 20 and wire 17 a at the other tieldpcoil terminal 20a.

Eachbrush 18 consists of a metal bushing 21 set into the cap 11 and held by the sleeve 22 integral with non-conducting material.

the said cap and also of Freely moving in the open end of the bushing is a carbon brush 23 adapted to bear upon. the commutator 19 and pressed inward against the same by a spiral spring 24. After the brush and spring are inserted in the bushing they are confined therein an a screw 25.

d the pressure of the so it may Renewed August. 19, 1925.

The spindle 26 of the armature is mounted in a bushing 27 of hard metal at the centre of the cap 11, the bushing being secured in thc thiinble Q8 of the cap, while the other end of the armature spindle is provided with a sleeve 29 playing in the hard metal bear ing 30 which carries the stem or hand piece 31 ot the tool, being connected by appropriate screw threads. In order to thoroughly insulate the armature from sleeve 29 an in sulating bushing 29 is disposed between the armature spindle and said bushing. The outer end of sleeve 29 has prongs 32 to engage the pin 33 of the tool spindle 34 and provide a loose but positive connection, easily disconnected when the stem 31 is removed.

In the form of bearing shown in Fig. 3 the bushing 30 is, dispensed with as the sleeve 29 provides abundant surface for the necessary support, and it the shell and its stem 35 are Aot' insulating or non-conductive inaterial, the length oi' the sleeve will be sutiicient with proper lubrication to adord a reliable bearing surface. The rear end spindle, as shown in Fig. L1, may also be journalled directly in the sleeve 36 of the cap 11 without the interposition of a hard metal sleeve.

In the construction shown in Fig. 5 the sleeve 29 has its bearing directly in thesteni 35 of the shell 1() but in order to secure the stem of the tool thereto, a sleeve 36 of steel or hard inetal is secured to the stem 35 and has screw threads in its interior to which the stem 31 may be screwed.

The screw joints at various parts of the device afford a ready means for gaining access to the interior of the shell and the parts are so grouped that they may be easily removed and separated for repair or renewal.

It is obvious that the parts may be otherwise arranged or modified without departing constructed entirely of insulating material forming an enclosure completely housthe rotor,

jecting reduced part of insulating material for connecting the motor and hand piece to form a unitary instrument suitable for carrying in the hand during performance of a surgical operation, said casing including a cap of insulating material removably secured to the casing, brushes carried by said cap for conduct-ing current to the motor armature, said motor having a rotor, field core and field coils mounted in said insulating casing, bearings carried by said reduced casing part and said insulating capfor supporting said rotor in concentric position with reference to said field coreand eld coils and a driving coupling'or said rotor for transmitting power to the operating 1mplement, said coupling being insulated to protect the hand piece land-implement from electrical connection With the rotor. l

' 2. A hand carried dental or surgical instrument including, in combination, a hand piece including a holder for an operatmg tool or implement, a motor includinga' casing constructed entirely of insulating 'material forming an enclosure completely heusing the motor and having a yforwardly projecting reduced part of lnsulating materlal forming a supporting stem, a stationary bearing sleeve securely seated in said supporting stem and being threaded to the. hand piece for connecting the motor and hand piece to form a unitary instrument suitable for carrying in the hand during the performance of a surgical operation, said casing including a cap of insulating material removably secured thereto, said motor having a rotor, eld core and feldcoils mounted in said insulating casing, a bearing in said insulating cap for supporting one end of arotary bearing sleeve rotatably supported in said-stationary bearing sleeve having a driving connection with said lmplement and a supporting connection with the other end of the rotor, said supporting connection being insulated to prevent shocking the patient or the operator by electrical connection with the rotor.

3. A hand carried dental or surgical instrument including, in combination, a hand piece including a holder for an operating tooll or implement, a motor including a casing constructed entirely. of insulating material forming an enclosure completely housing the motor and having rojecting integral reduced part of Vinsu ating material forming a supporting stem for connecting the motor and hand plece to form a unitary instrument suitable for carrying in the hand during performance of a surgical operation, said casing including a cap of insulating material removably secured to the casin said motor havin a rotor, field core and eld coils mounte in said insulating casing, and said eld core being mounted atei/,rae

-to form therewith a unitary instrument suitable for carrying in the hand during the performance of a surgical operation, a removable cap for said casing constructed of insulating material, a motor supported in said insulating casing and having a field core supported directly bythe casing and insertable therein and removable therefrom a bearing carried byl said removable when the cap is removed, an armature con-v centric with said field core, casing and ca and insulatedp bearings on said for supporting said armature agalnst electrical connection of the motor with thek operating implementl or hand piece, and'a'coupling for coupling the armature to the operating implement and being insulated 'to prevent electrical connection of the armature with the operating implement or hand piece.

5. In a motor in combination, an insulating casing having an integral bushing, a tool holder, means engaging said vbushing foirigidly supporting said holder on said casln'g, a rotor supported in said casing and adapted to be connected to said tool holder, and means for linsulating said tool holder from said rotor. Y 6. In a motor in combination, an insulating casing having an integral bushing, a tool holder, means engaging said bushing for rigidly supporting said holder on said casing, a rotor supported in bearings inteu-'rally formed in said casing and adapted to e connected to said tool holder, and means for insulating said tool holder from said rotor.

7. ln an electric motor, a ield structure, an armature, a shaft therefor, a rigid selfsupporting unitary insulating casing, forming a structural part of the motor and constituting the sole vsupport for the iield structure, a tubular metallic bushing into which one end of the armature shaft extends, supported by one end of the said insulating casing, and means carried by the bushing for attachment of the stationary part of a tool driven from the adjacent end of the armature shaft. 4

-8. In an electric motor, an armature, a shaft therefor, a rigid selfa field structure,

supporting unitary insulating casing, form- A ing a structuralpart of the motor and constituting the sole support for the field strucpart of a tool driven from the armature shaft.

VSigned at New York, in the'county of l0 'New York and State of N. Y., ths 6th day February, A. D. 1919.

HOVARD A. VHTESIDE. 

